The present invention relates to an absorption refrigerating unit with auxiliary gas and particularly to such a unit for cooling a plurality of refrigerating compartments.
Absorption refrigerating units with auxiliary gas are employed for use in refrigerators, particularly for non-electric operation. One embodiment is shown in FIG. 1 of the drawings hereof. In that embodiment, the coolant is expelled from a solution of coolant by feeding heat to it in a generator 1. The coolant vapor passes through the water separator 2 into the condenser 3. The coolant vapor is condensed in the condenser 3, and the liquid is conducted into the evaporator 5, where it evaporates with absorption of heat. In the absorber 4, the evaporated coolant is absorbed again with the liberation of heat by the solution which is lean in coolant.
The arrows shown in FIG. 1 give the direction of the auxiliary gas flow. The auxiliary gas coming from tube 27, into which the coolant evaporates, is a lean gas, which means that the concentration of evaporated coolant in the auxiliary gas is low. In the evaporator 5, the auxiliary gas is enriched by the evaporating coolant and becomes a rich gas.
The auxiliary gas leaving the absorber 4 has now a low concentration of coolant and is therefore a lead gas. It flows through a vertical column 29, which increases the performance of the cooling unit by cooling down the auxiliary gas. Water dropping out of the auxiliary gas runs back either into the absorber 4 or into tube 32. The lean gas flows through tube 27 back to the evaporator 5. There is no coolant and no evaporation in tube 27. A certain amount of lean gas flows from tube 27 through the precooler 30 to a bypass tube 28. The liquid coolant coming from the condenser 3 is cooled down in the precooler 30 by partial evaporation into the auxiliary gas passing the precooler 30 into the bypass tube 28.
The poor solution passing the absorber 4 downward absorbs the ammonia vapor out of the auxiliary rich gas. The solution leaving the absorber into the reservoir 33 is enriched by ammonia. The main part of the solution in the cooling unit is stored in the reservoir 33. The rich solution leaves the reservoir 33 and is transferred through the outer tube 35 of the liquid heat exchanger to the boiler 1. In the boiler 1, the ammonia is driven out of the rich solution by means of heat input. The poor solution leaves the boiler and runs through the inner tube 34 of the liquid heat exchanger back to the top 31 of the absorber 4.
The patent literature, particularly Federal Republic of Germany OS 2,449,372, discloses that instead of arranging the evaporator directly alongside the items to be cooled, the flow of heat from the items to be cooled to the evaporator is obtained through a closed secondary system. The use of an absorption refrigerating unit in the secondary system between the evaporator and the refrigerating compartments in a multi-temperature refrigerator of known construction results in low efficiency of the absorption refrigerating unit, which in turn causes a high consumption of energy by the absorption refrigerating unit.